Rotary switch



March 15, 1960 Filed Sept. 3, 1958 J. P. E. WATTERBERG 2,928,910

ROTARY SWITCH 2 Sheets-Sheet 1 INVENTOR. John R E. Waiterberg Allarn ey March 15, 1960 J. P. E. WATTERBERG 2,923,910

ROTARY SWITCH Filed Sept. 3, 1958 2 Sheets-Sheet 2 Fig. 3

IN V EN TOR.

John P. E. Wa/ferberg Attorney United States Patent ROTARY swrrcn John P. E. Watterberg, Albuquerque, N. Mex., assignor, by mesne assignments, to the United States of America as represented by the United States Atomic Energy Commission Application September '3, 1958, Serial No. 758,876

7 Claims. (Cl. 200-44) My invention relates to rotary electrical switches, and more particularly to those switches designed for use with voltages of the order of thousands of volts.

At voltages of that magnitude, the possibility of arcing occurring between contacts when the switch is open leads to the design of switches having large air gaps between the contacts. This makes necessary the provision of long contact arms which are inherently susceptible to vibration. The length of the contact arms also adds needlessly to the size of the individual switch.

In my invention, which I presently will describe, I have provided a high-voltage switch which operates by rotary action and which relies on a long creepage path over a dielectric surface to prevent arcing when the switch is open. In avoiding the use of long contact arms I have provided a switch which is unusually rugged and insensitive to vibration and which is considerably smaller than switches of the prior art. The switch is particularly adaptable for remote control, and I have provided a unique motor control and indicator system which affords operation of the switch with a small amount of power, no power being needed to hold the switch in either the open or the closed position.

Very briefly, the structure of my invention includes a movable insulating shell which separates the contacts of the switch in the Off position and which allows the contacts, at least one of which is spring-mounted, to mate in the On position. In its smallest form, the switch has the shape of a cylinder, the movable insulating cylindrical shell moving within an outer cylinder and separating the contacts except when an aperturein the member allows the contacts to mate. Mounted on the movable shell are conducting segments which work in conjunction with conducting brushes to stop an electrical motor from further turning the shell when the contacts are mated. Additional similar conducting segments and brushes control an indication of the position of the movable shell.

In the more detailed description to follow, I have provided a better understanding of the invention and its additional advantages. The description should be read in conjunction with the attached drawing, in which:

Fig. 1 is an exploded perspective view of a preferred embodiment of the invention;

Fig. 2 is a cross-sectional view, taken along the line 2-2 of Fig. l; and

Fig. 3 is a schematic diagram of an exemplary electrical circuit including the preferred embodiment and suggested control and indicating circuits.

Referring now to Figs. 1 and 2, inner insulating cylinder is seen to be rotatably mounted within outer insulating cylinder 11. Both cylinders may be made of diallyl phthalate plastic and an acrylic synthetic fiber filter, but other insulating materials are suitable. Equally spaced about the periphery of cylinder 11 are four conducting contacts 12, 13, 14, and 15, each contact extending through the inner surface of the cylinder. Four springmounted contacts 16, 17, 18, and 19 are mounted within outer cylinder 11 so as to extend within inner cylinder 10 in mating relationship to contacts 12, 13, 14, and 15, respectively. Crossarm 20 holds the spring-mounted contacts in position and conductively connects opposite contacts.

In the position shown, the wall of cylinder 10 is interposed between mating contacts of contact pairs 15-19 and 14'18, while a pair of circumferential diametrically opposed slots in the wall allow spring-mounted contacts 16 and 17 to mate with contacts 12 and 13, respectively. Arcing between contacts 14 and 15 is effectively prevented by the long creepage path between the contacts along the outer and inner surfaces of outer cylinder 11. Rotation of inner cylinder 10 ninety degrees clockwise from the position shown aligns the circumferential slots with contact pairs 15-19 and 14--18, allowing the contacts of each pair to mate,-while the cylinder wall is interposed between the contacts of pairs 1216 and 13--17. Beveled ends of the slots allow the spring-mounted contacts to ride up onto the inner surface of the cylinder wall during rotation.

It is seen that in the preferred embodiment shown, the switch acts to bridge the gap between two outside contacts in the On position. Since there are two pairs of outside contacts, the switch alternately connects contacts of one pair, then of the other. Numerous variations from this embodiment may be made according to the demands of associated circuitry. For instance, a voltage may be suppled to terminal 21, operation of the switch thenconnecting the voltage to each of two outer contacts. Or the number of outer contacts may be reduced to two or even one.

The embodiment having only two diametrically opposed outer contacts provides double the creepage path between contacts, compared to the preferred embodiment. Of course, for a given voltage'requirement the size of the switch (and hence the distance between contacts) may be chosen accordingly, in. any given embodiment.

If only one outer contact and a mating spring-mounted contact are used in conjunction with a single slot in the inner cylinder, the maximum voltage handling capabilities of the switch are realized. In that case operation of the switch connects terminal 21 to an outer contact by means of crossarm 20 and a spring-mounted contact. In the Off position of the switch, the slot in the inner cylinder is disposed diametrically opposite the mating contacts, with the cylinder wall interposed between the contacts. This provides a very long electrical creepage path within the switch, and another long path between terminal 21 and the outer contact by way of the right end of the switch, as shown in Fig. 1.

Rotation of the inner cylinder may be accomplished manually or mechanically. In the preferred embodiment the inner cylinder may be rotated by means of an electric motor (not-shown in Fig, 1). A pair of conducting segments 22 mounted within inner cylinder 10 cooperate with several, brushes 23 to stop rotation when the switch reaches the desired position.' Other conducting segments 24 cooperate with brushes 25 and a suitable indicating circuit to show the position of the inner cylinder, and hence the On or 01f condition of the switch.

The motor may have its driving shaft connected to shaft 26 of the inner cylinder, while electrical connections to the motor and to the indicating circuits may be made by means of end terminals 27.

In the schematic diagram of Fig. 3, motor 31 is shown as mechanically connected to turn electrical portions of the switch. Outer contacts 12 and 13 are shown electrically connected by the switch, completing circuit A. Circuit B awaits completion after a rotation of the switch. Indication of the switch position is provided by lamp 32, which is lighted due to the bridging action of conducting segment 24 in coopera-- warm tion with brushes 25 and the voltage which is constantly applied to a pair of the brushes.

As shown, no voltage is being applied to the motor,

so it is stationary. When switch 33 is operated to its other positiomhowever, voltage is applied to the motor by means of conducting segmentZZ and brus hes 23, causing the motor to turn the inner cylinder. At ap proximately 90 rotation from the position shown, a break in conducting segment 22 arrives under the voltage bearing brush, opening the motor power circuit and stopping rotation. At that position, lamp 34 is supplied with power due to the bridging of appropriate brushes by conducting segment ,24 and is lighted. At the same time, lamp 32 is unlighted. Operation of switch 33 back to the position shown causes further rotation of motor 31 for 90, extinguishing lamp 34 and lighting lamp 32 and in general creating the same electrical conditions as shown in Fig. 3, -but with the rotative parts rotated 180' from the position shown.

' I have shown and described a rotary electrical switch which is particularly useful in high-voltage circuits but which is applicable to low-voltage uses also. Although I have described in detail a preferred embodiment of my invention, it is not my intention to be limited thereto. Modifications and alternate embodiments will occur to one skilled in the art and may be practiced without departing from the sphere and scope of my invention as claimed below.

I claim as my invention:

1. A rotary electrical switch comprising an outer insulating cylinder having a first electrical contact extending through the inner surface of the cylinder, at second electrical contact spring mounted within the outer cylinder to mate with the first contact, an inner insulating cylinder rotatably mounted coaxially Within the outer cylinder and having an aperture adapted and arranged to allow mating of the contacts, the wall of the inner cylinder being interposed between the contacts in the ab sence of such radial alignment, electrical means for rotating the inner cylinder, means for controlling said rotation means, andmeans for indicating the angular position of the inner cylinder.

2. A rotary electrical switch, comprising an outer insulating cylinder having a first-pair of coplanar diametrically opposed electrical'contacts, and a second like pair, each contact extending through the inner surface of the cylindenand equally" spaced from adjacent contacts; a third pair of electrically joined contacts spring mounted within the outer cylinder to mate with said first pair of contacts; a fourth pair of electrically joined contacts spring mounted within the outer cylinder to mate with said second pair of contacts; an inner insulating cylinder rotatably mounted coaxially within the outer cylinder and having a pair of diametrically opposed circumferential slots each adapted and arranged to allow mating of a spring-mounted contact with the corresponding contact only during a fraction of a revolution of the inner cylinder, the wall of the inner cylinder being interposed between the contacts during the remainder of the revolution, electrical means for rotating the inner cylinder;

means for controlling said rotation means; and electrical means for indicating the angular position of the inner cylinder.

3. A rotary electrical switch comprising an outer insulating cylinder having a first electrical contact extending through the inner surface of the cylinder, an insulating support member positioned coaxially within said outer cylinder and joined integrally therewith at adjacent ends thereof, and forming therewith a cylindrical channel, a second electrical contact spring-mounted on said support'member to mate with the first contact, and an intermediate insulating cylinder rotatably supported within and longitudinally positioned by said cylindrical channel and having a circumferential aperture facilitating mating of the first and second contacts when said aperture is radially aligned therewith.

4. A rotary electrical switch as in claim 3 including electrical means for rotating the inner cylinder, means forco'ntrolling said rotation means, and means for indicating the angular position of the inner cylinder.

5 A rotary electrical switch comprising an outer insulating cylinder having a first pair of coplanar diametrically oppo sed electrical contacts and a second like pair, each Contact extending through the inner surface of the cylinder and equally spaced from adjacent contacts, an insulating support member positioned coaxially within said outer'cylinder and joined integrally therewith at adjacent ends thereof, and forming therewith a cylindrical channel, a third pair of electrically joined contacts, spring-mounted on said support member to mate with said first pair of contacts, a fourth pair of electrically joined contacts spring-mounted on said support member to mate with said second pair of contacts, an intermediate insulating cylinder rotatably supported within and longitudinally positioned by said cylindrical channel and having a pair of diametrically opposed circumferential slots each adapted and arranged to allow mating of a spring-mounted contact with the corresponding contact only during a fraction of a revolution of the inner cylinder, the wall of the inner cylinder being interposed between the contacts during the remainder of the revolution.

6. A rotary electrical switch as in claim 5 including electrical means for rotating the inner cylinder, means for controlling said rotation means, and electrical means for indicating the angular position of the inner cylinder.

7. A rotary electrical switch as in claim 3 wherein the intermediate cylinder is provided with at least one circumferentially extending conducting segment isolated from said aperture by a transverse insulating wall.

References Cited in the file of this patent UNITED STATES PATENTS 2,335,529 Panissidi Nov. 30, 1943 2,337,889 Harlow et al. Dec. 28, 1943 2,493,419 Puffer Jan. 3, 1950 2,510,067 Callander June 6, 1950 2,714,144 Amundson July 26, 1956 

